Step 1: consult a doctor to determine:
- If it's really hemorrhoids
- The severity if it is
- And the protocol to remedy it.
If the hemorrhoid was caused by lifting, then know it won't get any better if you continue lifting the way you do. You can work through minor hemorrhoids, but refine your technique.
Step 2: fix your form
You'll find that you need to keep a rigid body to perform the lifts well. However, you may be misunderstanding the intent behind the cues you hear or read.
"Squeeze the Glutes"
This cue is not talking about squeezing the cheeks together. It is referring to engaging the gluteal muscles for the purpose of standing back up with a loaded bar. It's more about hip extension than it is sphincter control.
Perhaps a better cue for you would be to "get tight".
Increase overall tightness
The first thing to master is how to breath for lifting. A proper breath will help brace your body better and complete the lift without endangering yourself. The following steps are applicable to squat and bench press, with only slight modifications needed for deadlift:
- unrack the bar (not necessary on deadlifts)
- Inhale into your spine. You should have equal pressure all the way around your core
- Hold that breath until exertion is over. For the squat and bench, that's down and up. For deadlift that's until you are in the upright position or when the bar is back on the ground.
The purpose of that breath is to provide core stability. It not only helps you lift more weight, it also helps the rest of your musculature do what it is supposed to do.
Getting tight also affects your posture. The upper back is braced and ready for the pull, squat, or press. Same with the abs, legs, hip muscles, etc. The more rigid you can make your body in a good posture, the more you'll be able to lift.